JPH0510217B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a hot press suitable for bonding multilayer printed wiring boards of various electronic devices such as computers.

[Background of the invention]

In recent years, in order to realize high-density mounting of components onto a molded object such as a printed wiring board, there has been a trend toward multilayering a plurality of printed wiring boards.

Conventionally, in a hot press that heats and pressurizes a plurality of printed wiring boards in multiple layers, a lower polster 4 is placed on a ram 3 of a main ram cylinder 2 fixed to a lower press frame 1, as shown in FIG. A lower heating plate 6 is fixed on the lower polster 4 via a lower heat insulating plate 5, and an intermediate heating plate 7 is supported by a counter cylinder 8 on the upper part provided with an opening for carrying in and out of the adherend. In the upper part, an upper heating plate 9 is thermally insulated by an upper heat insulating plate 10, and is fixed to an upper polster 12 connected to the lower press frame 1 by struts 11.

In this hot press, objects 13 such as multilayer printed wiring boards are inserted between a lower hot plate 6 and an intermediate hot plate 7, and between an intermediate hot plate 7 and an upper hot plate 9, and each hot plate 6,
7 and 9 from the heating/cooling control device 14, and at the same time, hydraulic pressure is supplied from the hydraulic device 15 to the main ram cylinder 2 and the counter cylinder 8 to pressurize and bond the object 13. .

By the way, in order to uniformly heat or cool the hot plates, the steam and cooling water passages of the hot plates 6, 7, and 9 are connected to the hot plates so as to connect the inlets and outlets at the ends of the hot plates, as shown in FIGS. 2 and 3. Parallel or series passages run along the center plane.

However, in the passage shown in FIG. 2, although the amount of steam and cooling water flows uniformly through each passage, since the passage is long, a temperature difference occurs due to the difference in the amount of heat absorbed at the inlet and outlet. Therefore, a uniform hot plate surface temperature distribution can be obtained during constant temperature control with a small amount of heat absorbed, but during heating and cooling processes where a large amount of heat is absorbed, the difference in hot plate surface temperature near the inlet and near the outlet becomes large. On the other hand, in the passage shown in Fig. 3, the length from the entrance to the exit is shorter, but
Since the distribution of steam and cooling water in the parallel passages is not uniform, variations occur due to differences in the amounts of steam and cooling water.

This variation in temperature distribution during the heating and cooling process is caused by the softening, melting, and hardening times of the adhesive prepreg being different depending on the bonded area, resulting in the generation of residual air bubbles (voids) and dimensional changes in the multilayer printed wiring board. This has the problem of increasing variations and lowering reliability.

[Purpose of the invention]

In view of the above-mentioned points, the present invention has developed a hot press capable of forming adherends with little dimensional change and no residual bubbles by heating and pressing with a hot plate that provides a uniform surface temperature distribution even during heating and cooling processes. The purpose is to provide.

[Summary of the invention]

It is believed that it is necessary to manufacture highly accurate hot presses in order to mold objects to be adhered such as highly accurate multilayer printed wiring boards, and we have been pursuing mechanical methods to improve accuracy. However, experimental results have revealed that unless measures are taken to improve mechanical precision and temperature distribution throughout the entire bonding process, a multilayer printed wiring board with little dimensional change and no residual bubbles can be obtained. As a measure to obtain a uniform temperature distribution in this entire bonding process, the present invention comprises upper and lower polsters driven relative to each other by a ram cylinder, and a hot plate having steam and cooling water passages between the upper and lower polsters, In a hot press in which objects to be bonded inserted between the hot plate and the upper and lower polsters are bonded using the forming heat energy of the hot plate and the pressure of the upper and lower polsters, the steam of the plurality of cells installed in the hot plate is used. and cooling water passages are arranged in parallel, each formed in a U shape, and each has one end connected to a water supply port and the other end connected to a drain port.

[Embodiments of the invention]

Hereinafter, one embodiment of the hot press of the present invention will be described in the fourth example.
This will be explained with reference to FIGS. 5 and 6.

In FIGS. 4, 5, and 6, the same reference numerals as in FIG. 1 indicate the same parts.

16 is a lower heating plate fixed on the lower insulation plate 5;
An intermediate hot plate 17 having an opening for carrying in and out of adherends at the top is supported by a counter cylinder 8, and an upper hot plate 18 at the top is thermally insulated by an upper heat insulating plate 10. These hot plates 16, 17
and 18, as shown in FIG.
2, a drain port 23, and a steam and cooling water passage 24.

In the fifth, the steam and cooling water passage 24 is U-shaped, and both opening ends thereof are connected to the distribution chamber 19 and gathering chamber 20 of a set of headers 21, respectively, and the end connected to one distribution chamber 19 is a water supply port. The distance from 22 increases as the distance increases. The cross-sectional shapes of the distribution chamber 19 and the gathering chamber 20 of the header 21 are formed to be larger than the passage area of the steam and cooling water passage 24. Therefore, steam and cooling water are supplied from the water supply port 22 to the header 21.
and is supplied to each heating and cooling passage 24 within the hot plate with equal flow distribution. The steam and cooling water that have been heat exchanged in the passage 24 pass through the gathering chamber 20 of the header 21 and are discharged to the drain port 2.
It is discharged from 3.

In addition, since the cross-sectional shapes of the distribution chamber 19 and the gathering chamber 20 of the header 21 have a constant branching and confluence loss, the flow rate can be evenly distributed to the steam and cooling water passages 24 of the hot plates 16, 17, and 18, and further,
Since the passage 24 is connected to the distribution chamber 19 every round trip, the temperature of the heat medium changes due to heat exchange in the middle of the passage, and the amount of heat exchange changes near the passage, but on the surface of the hot plate away from the passage, there is a difference between the outward and return passages. is an average value, and a uniform temperature distribution can be obtained on the hot plate surface even during the temperature rising or cooling process.

FIG. 6 shows another embodiment of the hot press of the present invention, in which uniform flow distribution is achieved without providing a distribution or gathering chamber, and one in which the amount of heat exchanged due to temperature change of the heating medium is adjusted in the middle of the passage. One round-trip path for canceling is arranged above and below.

〔Effect of the invention〕

According to the hot press of the present invention, the temperature distribution during heating and cooling of the adherend can be made uniform, so it is possible to mold the adherend with little dimensional change and no residual bubbles.

Therefore, when the object to be bonded is used for bonding work of multilayer printed wiring boards, for example, a great effect is exhibited.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the structure of a conventional hot press, FIGS. 2 and 3 are cross-sectional views taken along the - line and - line in FIG. A front view showing the structure of the hot press, and FIGS. 5 and 6 are three-dimensional views of the hot plate. 1... Lower frame, 2... Ram cylinder, 3
...Ram, 4...Lower bolster, 5...Lower insulation board, 6...Lower heating plate, 7...Intermediate heating plate, 9...Upper heating plate, 10...Upper insulation board, 12...Upper bolster ,
14... Heating cooling device, 15... Hydraulic device, 16
...Lower hot plate, 17...Middle hot plate, 18...Upper hot plate, 19...Distribution chamber, 20...Collection room, 24...
Heat medium passage.

Claims (1)

[Scope of Claims] 1. A device comprising upper and lower polsters that are relatively driven by a ram cylinder, and a hot plate having steam and cooling water passages between the upper and lower polsters, and between the hot plate and the upper and lower polsters. In the hot press, which bonds the inserted objects to be bonded using the forming heat energy of the hot plate and the pressure of the upper and lower polsters, the plurality of steam and cooling water passages installed in the hot plate are arranged in parallel, and each U A hot press characterized in that it is formed into a shape and has one end connected to a water supply port and the other end connected to a drain port. 2. The hot press according to claim 1, wherein both ends of the plurality of steam and cooling water passages are connected to the water supply port and the drain port via a set of distribution/collection pipes. 3. The distribution/collection pipe is characterized in that its internal volume is larger than the passage area of the steam and cooling water passage, and the end lengths of the steam and cooling water passage connected to the distribution pipe are different. A hot press according to claim 2. 4. The hot press according to claim 1, wherein the plurality of steam and cooling water passages have an outgoing path and a returning path arranged in the thickness direction (vertical direction) of the hot plate.